Automatic septum-changing mechanism

ABSTRACT

A septum-changing inlet apparatus for chromatographs having a ported body and a septum strip moved linearly in successive increments relative to the port of said body to overlie said port with unused or imperforated parts of the septum strip. A septum compression plate movable between a position pressing the septum strip, overlying the port of the body against the face of the inlet and a septum release position. Fluid pressure actuated means is adapted to move said plate and as said plate is actuated or moved, the septum strip is moved linearly.

Inventor Tom l-l. Vannus Pomona, Calif.

Appl. No. 46,696

Filed June 16, 11970 Patented Dec. 21, 11971 Assignee Hamilton CompanyWhittier, Cnlili.

AUTOMATIC SEllTlJM-CllllANGllNG MECHANISM 8 Claims, 3 Drawing l igs.

U.S. Cl 73/422 GC lint. Cl Glllln ll/lltl Field of Search 73/422 GC,

[56] lllelerences Qited UNITED STATES PATENTS 3,431,783 3/1969 Radgens73/422 GC 3,566,697 3/1971 Vannus 73/422 GC Primary Examiner-S. ClementSwisher Attorney-J. Carroll Baisch AhSTllllACT: A septum-changing inl-etapparatus for chromatographs having a ported body and a septum stripmoved linearly in successive increments relative to the port of saidbody to overlie said port with unused or imperlorated parts of theseptum strip. A septum compression plate movable between a positionpressing the septum strip, overlying the port of the body against theface of the inlet and a septum release position. Fluid pressure actuatedmeans is adapted to move said plate and as said plate is actuated ormoved, the septum strip is moved linearly.

PATENTEU BEBZ'I mm S U N N A V H M O T AGENT.

AUTOMATIC SElPTllJM-CI-IANGING MECIIAI IISM CROSS-REFERENCES TO RELATEDAPPLICATIONS John D. Reid, Chromatograph Inlet with Rotating Septumfiled Dec. 18, 1969, Ser. No. 886,142.

BACKGROUND OF THE INVENTION 1. Field of the Invention This inventionrelates generally to inlets for chromatographs and relates moreparticularly to chromatograph inlets having a septum that can beautomatically moved to bring various parts thereof into operativeposition.

2. Description of the Prior Art Conventional inlets for chromatographshave various problems, disadvantages and operating difficulties. As iswell known, septums retain their sealing reliability for from six toinjections and then must be replaced. When such septums are replaced,the chromatograph instrument must be shut down and there is, of course,an interruption of carrier gas flow and a loss of carrier gas while theused septum is removed from the inlet and a new septum installed. Thereis a waiting period while the instrument regains its operatingtemperature after a shutdown. There is also always the danger that theoperator will have his fingers burned while changing the septum.

My previous instrument, disclosed in my copending application Ser. No.845,433 provides a septum changer wherein a septum disc is carried by arotatably mounted ratchet wheel having a plurality of annularly spacedouter ports which are successively moved into alignment with a port ofthe body of the chromatograph, there being means for successivelyrotating the ratchet wheel to move said outer ports respectively intoalignment with the port in the body.

The John D. Reid instrument, disclosed in his copending applicationfiled Dec. 18, 1969, Ser. No. 886,142, comprises a body for connectionwith a chromatograph column. There is a circular septum which is rotatedby a motor, the motor being operated for a predetermined period of timeto successively rotate the septum predetermined increments to bringunused parts of the septum into alignment with a column adaptor.

SUMMARY OF THE INVENTION The present invention moves a strip of septummaterial linearly or longitudinally an increment at a time to replace apart of the septum material that has been perforated several times by asyringe needle with a part of the material that has not been used.

Means is provided for pressing against the adjacent part of achromatograph inlet having the inlet opening for a needle that portionof the septum material to be used to provide a proper seal with saidinlet. After this part of the septum strip has been perforated a numberof times so that it no longer seals reliably the pressure on the part ofthe septum strip aligned with the inlet port of the chromatograph inletis relieved and the strip moved an increment to bring an unused partinto alignment with said inlet port. When the septum strip has been thusmoved, the pressure is again applied to provide a secure seal with thechromatograph inlet.

OBJECTS AND ADVANTAGES OF THE INVENTION It is an object of the inventionto provide a simple and effective automatic septum-changing mechanism.

Another object of the invention is to provide mechanism of thischaracter wherein a strip of septum material is moved linearly orlongitudinally. Such a strip may be of considerable length so that agreat many changes may be made because of the length of septum stripspossible.

The characteristics and advantages of the invention are furthersufficiently referred to in connection with the following detaileddescription'of the accompanying drawings which represent one embodiment.After considering this example, skilled persons will understand thatmany variations may be made without departing from the principlesdisclosed, and l contemplate the employment of any structures,arrangements or modes of operation that are properly within the scope ofthe appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS Referring to the drawings, which arefor illustrative purposes only:

FIG. I is a schematic side elevational view of mechanism embodying theinvention and partial section;

FIG. 2 is a top plan view thereof; and FIG. 3 is a partially explodedperspective view of the mechanism.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring more particularly tothe drawing, there is a chromatograph inlet 16 which may be of thestandard type, said inlet having an entrance part 112.

At the forward end of the inlet entrance I2 is a septum supporting andfeeding assembly indicated generally at 14, said assembly comprising aframe indicated generally at 15 including a frame member l6'having anupstanding septum compressor plate 113. There is a guide 20 carried bythe frame 15. Plate 13 has a bore 23 which aligns with the inlet port12. A knurled shaft 24 is located in frame 15 extending through the topportion of frame E4 on which a ratchet wheel 54 is mounted. Spacedforwardly from shaft 24 is an idler roller 26. The idler roller ismounted on a shaft 28 having both ends fixed to the frame of theassembly 14. The spacing between the knurled shaft 24 and the idlerroller 26 is such as to operably receive the septum strip 22.

Sufficient pressure is exerted on the septum by the knurled shaft toeffect lineal movement of the septum strip with rotation of said knurledshaft 24, said idler roller 26 serving as a backup for the septum stripso that said strip will be positively moved linearly upon rotation ofthe knurled shaft 24.

The frame of the septum supporting and feeding assembly has a pair ofcars 32 which are spaced apart and have aligned openings therein forpivot pin 30 which is rotatably mounted in a support means not shown.Pivot pin 30 is secured in said aligned openings.

Assembly 14 is pivoted on pin 30 so that the septum sup porting andfeeding assembly may be swung toward and away form the entrance 12 ofthe inlet Ml.

Means for actuating assembly 14 comprises a fluid pressure cylinder 36having an car 38 at one end and pivotally attached to an car 40 by meansof a pivot pin 42, said ear 40 being secured to a support 44. Cylinder36 has a piston, not shown, attached to a piston rod 46 extending fromthe opposite end from said cylinder 36 and pivotally connected at 48 tothe free end of lever 32. It is to be understood that piston rod 46passes through an opening provided therefor in the adjacent end ofcylinder 36 and packing means is provided to provide a seal for saidpiston rod 46. The cylinder and piston rod arrangement is well known.Cylinder 36 is provided with conduits 50 and 52 at respective ends foroperating fluid under pressure. There is means, not shown, forcontrolling the supply of pressure fluid to the conduits 50 and 52 andfor venting the respective ends of the cylinder 36 whereby the piston isactuated longitudinally in the cylinder 36.

Means for rotating the knurled shaft 24 is provided and includes aratchet wheel 54 secured to one end of said knurled shaft. A pair ofpawls 56 and 558 are disposed tangentially relative to the ratchet 34,said pawls being mounted at their forward ends as shown in FIGS. 1 and 2on pivot pins 60 and 62 which are parallel to each other and which areoperably attached to a bracket 64 attached to a fixed mounting notshown. Spring '70 has its ends secured in openings provided therefore inthe respective pawls 56 and 58, said spring yieldingly urging the pawlstoward each other.

Pawl 56 has a hook-shaped free end 72 adapted to engage the teeth 74 ofthe ratchet wheel and pawl 58 has a pointed free end 76 also adapted toengage the teeth 74 of the ratchet wheel.

When a portion of the septum strip 22 is being used, fluid pressure issupplied to the cylinder 36 by way of the conduit 52, the conduit 50then being vented to atmosphere so that the piston urges the lever 32upwardly causing the septum compressor plate 18 to press the septumtightly against the adjacent end of the inlet entrance 12. The needle ofa samplecarrying syringe is inserted into the port 23 provided thereforein the plate 18, said port being in alignment with the inlet openingorifice of the inlet so that said needle when forced through the septum22, will enter said inlet opening. Sample material discharged from thesyringe is thereby delivered into the inlet 10 and handled in the usualmanner by the chromotograph.

When the septum strip is to be moved to position, a fresh part of theseptum strip into operable relationship with the inlet, the cylinder 36is provided with pressure fluid by way of the conduit 50, the conduit 52then being vented to atmosphere so that the piston will move the lever32 in counterclockwise direction, as shown in FIG. 3, and cause theframe of the septum carrying and feeding mechanism to move away from theentrance 12 of the inlet. As the frame is thus moved, the hook 72 of thepawl 56 causes the ratchet wheel to move in a clockwise direction, asshown in FIG. 2, while at the same time, the point 76 of the pawl 58slips over the adjacent tooth and engages said adjacent tooth. Thisclockwise movement of the ratchet wheel causes the septum strip to bemoved linearly a limited increment. Fluid is then supplied to cylinder36 to cause the piston to move upwardly and actuate lever 32 in thecounterclockwise direction. As the frame of the septum supporting andactuating mechanism is thus caused to move towards the inlet entrance12, the ratchet wheel 54 is further moved in the clockwise direction tofurther move the septum strip which is then sealingly pressed againstthe entrance 12 in the inlet. With the clockwise movement of the ratchetwheel effected by pawl 58, the hooked end 72 of pawl 56 slips over theadjacent leading tooth of the ratchet wheel. The movements of theratchet wheel effected by pawls 56 and 58 when the septum carrying andfeeding assembly is moved away from and then toward the inlet, effectssufficient movement of the septum strip 22 to bring into alignment withthe port 23 and the inlet opening of the chromatograph inlet 10 animperforated or unused part of the septum strip.

The septum strip may be of any suitable character. As shown, the septumstrip comprises a plurality of layers of septum material which mayinclude a relatively soft central layer and somewhat harder layers ateach side of the central layer, the layers being molded or otherwisesuitably secured together.

The invention and its attendant advantages will be understood from theforegoing description and it will be apparent that various changes maybe made in the form, construction and arrangement of the parts of theinvention without departing from the spirit and scope thereof orsacrificing its material advantages, the product or article hereinbeforedescribed being merely by way of example, and I do not wish to berestricted to the specific form shown or uses mentioned except asdefined in the accompanying claims.

1 claim:

1. Automatic septum-changing mechanism, comprising:

A. Septum carrying and feeding assembly including:

a. a frame with a septum compression plate having a needle-receivingopening therethrough:

b. means for moving said frame and its compression plate between aforward position and a rearward position, a septum strip being adaptedto be operable disposed at the forward side of the compression plate,

c. and means for moving a septum strip linearly at the forward side ofthe compression plate when the compression plate is moved away from itsforward tgosition. 2. The invention defined by claim I wherein e meansfor for moving a septum strip linearly comprises a rotatably mountedknurled shaft engageable with said septum strip, said shaft beingrotated when the compression plate is moved from its forward position.

3. The invention defined by claim 2 wherein there is backup meansadjacent the knurled shaft and spaced forwardly therefrom.

4. The invention defined by claim 3, wherein the septum carrying andfeeding assembly is pivotally mounted for movement between its forwardposition and a rearward position.

5. The invention defined by claim 3, including guide means adjacentcarried by the frame from the knurled shaft for guiding a septum stripacross said compression plate.

6. The invention defined by claim 4, wherein the means for moving theframe and compression plate between the forward and rearward positionscomprises a fluid pressure operated actuator.

7. The invention defined by claim 2, including means for operablyrotating said knurled shaft to advance a septum strip as the compressionplate moves from its forward position to its rearward position and alsooperable rotates such knurled shaft in the same direction as said plateis moved from its rearward to its forward position.

8. The invention defined by claim 7 wherein said means for rotating saidknurled shaft comprises a ratchet wheel secured to said knurled shaftand a pair of pawls oppositely engaging said ratchet wheel, one of saidpawls effecting rotation of said knurled shaft in one direction when thecompression plate is moved rearwardly while the other pawl effectsrotation of said knurled shaft in the same direction when saidcompression plate is moved forwardly.

0' i t i i

1. Automatic septum-changing mechanism, comprising: A. Septum carryingand feeding assembly including: a. a frame with a septum compressionplate having a needlereceiving opening therethrough: b. means for movingsaid frame and its compression plate between a forward position and arearward position, a septum strip being adapted to be operable disposedat the forward side of the compression plate, c. and means for moving aseptum strip linearly at the forward side of the compression plate whenthe compression plate is moved away from its forward position.
 2. Theinvention defined by claim 1 wherein the means for for moving a septumstrip linearly comprises a rotatably mounted knurled shaft engageablewith said septum strip, said shaft being rotated when the compressionplate is moved from its forward position.
 3. The invention defined byclaim 2 wherein there is backup means adjacent the knurled shaft andspaced forwardly therefrom.
 4. The invention defined by claim 3, whereinthe septum carrying and feeding assembly is pivotally mounted formovement between its forward position and a rearward position.
 5. Theinvention defined by claim 3, including guide means adjacent carried bythe frame from the knurled shaft for guiding a septum strip across saidcompression plate.
 6. The invention defined by claim 4, wherein themeans for moving the frame and compression plate between the forward andrearward positions comprises a fluid pressure operated actuator.
 7. Theinvention defined by claim 2, including means for operably rotating saidknurled shaft to advance a septum strip as the compression plate movesfrom its forward position to its rearward position and also operablerotates such knurled shaft in the same direction as said plate is movedfrom its rearward to its forward position.
 8. The invention defined byclaim 7 wherein said means for rotating said knurled shaft comprises aratchet wheel secured to said knurled shaft and a pair of pawlsoppositely engaging said ratchet wheel, one of said pawls effectingrotation of said knurled shaft in one direction when the compressionplate is moved rearwardly while the other pawl effects rotation of saidknurled shaft in the same direction when said compression plate is movedforwardly.